43 



been made which have proven useful and have 

 remained, while others have been discarded. As 

 the first microscope was constructed in 15f)n it has 

 required nearly three centuries to bring the in- 

 strument up to its present general form and it is 

 interesting to note that many improvements 

 which have been introduced within the last forty 

 or fifty years have been used and lost sight of 

 within this time. 



While certain parts are necessary to make up a 

 modern instrument, no one design of construction 

 is followed. The forms are innumerable, each 

 maker following his own inclination in varietv, 



o J * 



design, number of parts and material. For the 

 latter brass predominates, although bronze and 

 iron are used to a considerable extent. The first 

 two metals are usually highly finished and as they 

 easily tarnish, are protected by lacquer, which is 

 not only serviceable in this direction when well 

 done, but offers a means of ornamentation. Iron 

 is covered with a heavy coating of japan and be- 

 ing dark is on this account often recommended by 

 instructors as being agreeable for the eyes. The 

 entire apparatus, including the optical parts, is 

 called a microscope, whereas, without them, it is 

 termed a stand. Some people call it a "machine," 

 but we earnestly protest against this harsh term 

 as applied to an instrument of such precision as 

 the microscope is. 



